From fb8585fc3f9b39153e0bdaf03f00a02dde9c03c6 Mon Sep 17 00:00:00 2001
From: Roel Kluin <roel.kluin@gmail.com>
Date: Tue, 24 Mar 2009 03:27:48 +0000
Subject: ctcm: avoid wraparound in length of incoming data
Since the receive code should tolerate any incoming garbage, it
should be protected against a potential wraparound when manipulating
length values within incoming data.
block_len is unsigned, so a too large subtraction will cause a
wraparound.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/s390/net/ctcm_fsms.c | 5 ++---
drivers/s390/net/ctcm_main.c | 3 ++-
2 files changed, 4 insertions(+), 4 deletions(-)
(limited to 'drivers/s390')
diff --git a/drivers/s390/net/ctcm_fsms.c b/drivers/s390/net/ctcm_fsms.c
index f29c7086fc1..4ded9ac2c5e 100644
--- a/drivers/s390/net/ctcm_fsms.c
+++ b/drivers/s390/net/ctcm_fsms.c
@@ -410,9 +410,8 @@ static void chx_rx(fsm_instance *fi, int event, void *arg)
priv->stats.rx_length_errors++;
goto again;
}
- block_len -= 2;
- if (block_len > 0) {
- *((__u16 *)skb->data) = block_len;
+ if (block_len > 2) {
+ *((__u16 *)skb->data) = block_len - 2;
ctcm_unpack_skb(ch, skb);
}
again:
diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index 59ce7fb7308..a7a25383db7 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -105,7 +105,8 @@ void ctcm_unpack_skb(struct channel *ch, struct sk_buff *pskb)
return;
}
pskb->protocol = ntohs(header->type);
- if (header->length <= LL_HEADER_LENGTH) {
+ if ((header->length <= LL_HEADER_LENGTH) ||
+ (len <= LL_HEADER_LENGTH)) {
if (!(ch->logflags & LOG_FLAG_ILLEGALSIZE)) {
CTCM_DBF_TEXT_(ERROR, CTC_DBF_ERROR,
"%s(%s): Illegal packet size %d(%d,%d)"
--
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